Question 1

Which of the following best explains why Mendel's experiments with pea plants were successful in uncovering the basic principles of inheritance?

Accepted Answer

He used pea plants that naturally self-fertilize, allowing him to control pollination and track traits across generations.

Question 2

A heterozygous pea plant with genotype $$Pp ($$where $$P is $$purple and $$p is $$white) is self-fertilized. According to Mendel's laws, what is the expected phenotypic ratio of purple to white flowers in the offspring?

Accepted Answer

$$3:1$$

Question 3

Which of the following scenarios best illustrates the concept of independent assortment?

Accepted Answer

A plant with genotype $$YyRr$$ produces gametes $$YR$$, $$Yr$$, $$yR$$, and $$yr in $$equal proportions.

Question 4

Which of the following best describes the difference between genotype and phenotype?

Accepted Answer

Genotype refers to the genetic makeup (e.g., $$PP$$, $$Pp$$, $$pp$$), while phenotype refers to the observable trait (e.g., purple or white flowers).

Question 5

A man with blood type $$AB$$ and a woman with blood type $$O$$ have a child. Which blood types are possible for their child?

Accepted Answer

Type $$A or $$type $$B$$

Question 6

Which of the following is an example of incomplete dominance?

Accepted Answer

A cross between red-flowered and white-flowered snapdragons produces pink-flowered offspring.

Question 7

Which of the following best explains why sex-linked traits are more commonly expressed in males than in females?

Accepted Answer

Males have only one X chromosome, so a single recessive allele on the X chromosome will be expressed.

Question 8

A woman who is a carrier for hemophilia (an X-linked recessive disorder) marries a man who does not have hemophilia. What is the probability that their son will have hemophilia?

Accepted Answer

$$50\%$$

Question 9

Which of the following best describes pleiotropy?

Accepted Answer

A single gene influences multiple phenotypic traits.

Question 10

Which of the following is a real-world example of codominance?

Accepted Answer

A person with genotype $$IAIB$$ has both A and B antigens on their red blood cells.

Question 11

Which of the following best explains why linked genes do not always assort independently?

Accepted Answer

They are located close together on the same chromosome and tend to be inherited together.

Question 12

If a genetic disorder is caused by a recessive allele, what is the probability that two heterozygous parents will have an affected child?

Accepted Answer

$$25\%$$

Question 13

Which of the following is an example of a polygenic trait?

Accepted Answer

Human skin color, which is influenced by several genes.

Question 14

Which of the following best describes the effect of the environment on gene expression?

Accepted Answer

Environmental factors can influence the expression of genes, such as temperature affecting fur color in Himalayan rabbits.

Question 15

A woman with genotype $$X^AX^a ($$where $$X^A is $$normal and $$X^a is $$for color blindness) and a man with genotype $$X^AY$$ have a child. What is the probability that their daughter will be color blind?

Accepted Answer

$$0\%$$

Question 16

Which of the following statements about Huntington disease is correct?

Accepted Answer

It is caused by a dominant allele, so only one copy is needed for the disorder to be expressed.

Question 17

Which of the following best explains why carriers of sickle-cell anemia have a selective advantage in certain regions?

Accepted Answer

Carriers are resistant to malaria, which is prevalent in some regions.

Question 18

Which of the following is a correct statement about crossing over?

Accepted Answer

Crossing over increases genetic variation by exchanging DNA between homologous chromosomes.

Question 19

Which of the following best describes the inheritance pattern of a trait that appears in every generation and affects both males and females equally?

Accepted Answer

Autosomal dominant

Question 20

Which of the following is a likely outcome if a gene is located very far from the centromere on a chromosome?

Accepted Answer

It is more likely to be separated from other genes on the same chromosome during crossing over.

Patterns of Inheritance: Mendelian Genetics and Human Genetic Disorders

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